7.k8s.调度器scheduler 亲和性、污点

#k8s. 调度器scheduler 亲和性、污点

#指定调度节点

# Pod.spec.nodeName 强制匹配，直接指定Node 节点，跳过 Scheduler 调度策略

#node-name-demo.yaml

apiVersion: apps/v1beta1

kind: Deployment

metadata:

  name: demo-nodename

spec:

  replicas: 3

  template:

    metadata:

      labels:

        app: demo1

    spec:

      nodeName: node03  #指定Node节点

      containers:

      - name: demo1

        image: alivv/nginx:node

        ports:

        - containerPort: 80

#部署

kubectl apply -f node-name-demo.yaml

#查看pod全部在node03上 (node03节点不存在会一直处于pending)

kubectl get pod -o wide

#删除

kubectl delete -f node-name-demo.yaml

# Pod.spec.nodeSelector 强制约束，调度策略匹配 label，调度 Pod 到目标节点

#node-selector-demo.yaml

apiVersion: apps/v1beta1

kind: Deployment

metadata:

  name: demo-node-selector

spec:

  replicas: 3

  template:

    metadata:

      labels:

        app: demo1

    spec:

      nodeSelector:

        test1: node  #匹配lable test1=node

      containers:

      - name: demo1

        image: alivv/nginx:node

        ports:

        - containerPort: 80

#部署

kubectl apply -f node-selector-demo.yaml

#查看pod处于pending

kubectl get pod -o wide

#给node02节点添加lable

kubectl label nodes node02 test1=node

kubectl get nodes --show-labels

#再次查看pod在node02节点

kubectl get pod -o wide

#删除

kubectl delete -f node-selector-demo.yaml

kubectl label nodes node02 test1-

亲和性调度

亲和性调度可以分成软策略和硬策略两种方式

• preferredDuringSchedulingIgnoredDuringExecution：软策略，没满足条件就忽略，Pod可以启动
• requiredDuringSchedulingIgnoredDuringExecution：硬策略，没满足条件就等待，Pod处于Pending

操作符

• In：label 的值在某个列表中
• NotIn：label 的值不在某个列表中
• Gt：label 的值大于某个值
• Lt：label 的值小于某个值
• Exists：某个 label 存在
• DoesNotExist：某个 label 不存在

#节点亲和性 pod.spec.nodeAffinity

#node-affinity-demo.yaml

apiVersion: apps/v1beta1

kind: Deployment

metadata:

  name: node-affinity

  labels:

    app: affinity

spec:

  replicas: 3

  template:

    metadata:

      labels:

        app: affinity

    spec:

      containers:

      - name: nginx

        image: alivv/nginx:node

        ports:

        - containerPort: 80

          name: nginxweb

      affinity:

        nodeAffinity:

          requiredDuringSchedulingIgnoredDuringExecution:  #硬策略,不在node01节点

            nodeSelectorTerms:

            - matchExpressions:

              - key: kubernetes.io/hostname

                operator: NotIn

                values:

                - node01

          preferredDuringSchedulingIgnoredDuringExecution:  #软策略,优先匹配test2=node

          - weight: 1

            preference:

              matchExpressions:

              - key: test2

                operator: In

                values:

                - node

#给node03节点添加lable

kubectl label nodes node03 test2=node

kubectl get nodes --show-labels

#部署

kubectl apply -f node-affinity-demo.yaml

#查看pod

kubectl get pod -o wide

#删除

kubectl delete -f node-affinity-demo.yaml

kubectl label nodes node03 test2-

#Pod亲和性pod.spec.affinity.podAffinity/podAntiAffinity

#pod-affinity-demo.yaml

apiVersion: apps/v1beta1

kind: Deployment

metadata:

  name: pod-affinity-demo

  labels:

    app: pod-affinity

spec:

  replicas: 3

  template:

    metadata:

      labels:

        app: pod-affinity

    spec:

      containers:

      - name: nginx

        image: alivv/nginx:node

        ports:

        - containerPort: 80

          name: nginxweb

      affinity:

        podAffinity:

          requiredDuringSchedulingIgnoredDuringExecution:  #硬策略

          - labelSelector:  #匹配Pod有 app=demo1

              matchExpressions:

              - key: app

                operator: In

                values:

                - demo1

            topologyKey: kubernetes.io/hostname

#部署

kubectl apply -f pod-affinity-demo.yaml

#查看pod全部处于Pending 因为没标签app=demo1的Pod

kubectl get pod -o wide

#部署上面的node-name-demo.yaml

kubectl apply -f  node-name-demo.yaml

#再次查看pod全部在node03节点

kubectl get pod -o wide

#Pod反亲和性测试

#改podAffinity为podAntiAffinity

sed -i 's/podAffinity/podAntiAffinity/' pod-affinity-demo.yaml

kubectl apply -f pod-affinity-demo.yaml

#查看node03节点移除pod-affinity-demo

kubectl get pod -o wide

#删除

kubectl delete -f pod-affinity-demo.yaml

kubectl delete -f node-name-demo.yaml

# 污点taints与容忍tolerations

污点设置 kubectl taint nodes node-name key=value:effect

key 和 value 为污点标签， value 可以为空，effect 描述污点的作用，effect 支持如下三个选项：

• NoSchedule 不会将 Pod 调度到有污点的 Node
• PreferNoSchedule 避免将 Pod 调度到有污点的 Node
• NoExecute 不会将 Pod 调度到有污点的 Node ，将已经存在的 Pod 驱逐出去

#给node03添加污点

kubectl taint nodes node03 test-taint=node:NoSchedule

#查看

kubectl describe node node03 |grep Taints

容忍 pod.spec.tolerations

#pod-tolerations-demo.yaml

apiVersion: apps/v1beta1

kind: Deployment

metadata:

  name: pod-tolerations-demo

  labels:

    app: pod-tolerations

spec:

  replicas: 3

  template:

    metadata:

      labels:

        app: pod-tolerations

    spec:

      containers:

      - name: nginx

        image: alivv/nginx:node

        ports:

        - containerPort: 80

          name: http

#创建Pod

kubectl apply -f pod-tolerations-demo.yaml

#查看Pod，node03节点有污点将不会创建Pod

kubectl get pod -o wide

#文件pod-tolerations-demo.yaml追加容忍污点配置

echo '#容忍污点

      tolerations:

      - key: "test-taint"

        #value: "node"

        operator: "Exists"  #忽略value值

        effect: "NoSchedule"

'>>pod-tolerations-demo.yaml

cat pod-tolerations-demo.yaml

#更新

kubectl apply -f pod-tolerations-demo.yaml

#Pod扩容

kubectl scale deployment pod-tolerations-demo --replicas 5

#再次查看Pod，Node03有Pod

kubectl get pod -o wide

#删除Pod

kubectl delete -f pod-tolerations-demo.yaml

#删除污点

kubectl taint nodes node03 test-taint-

#不指定 key 值时，容忍所有的污点 key

tolerations:

- operator: "Exist

#不指定 effect 值时，表示容忍所有的污点作用

tolerations:

- key: "key"

  operator: "Exist"

#避免资源浪费，设置master运行Pod，可以如下配置：

kubectl taint nodes --all  node-role.kubernetes.io/master- #先删除默认污点

kubectl taint nodes Node-Name node-role.kubernetes.io/master=:PreferNoSchedule

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